1. Field of the Invention
The invention relates to an output apparatus in which data constructing a page is received from a host computer, a character code or graphic data transmitted from the host computer is developed into a bit map, image data transmitted from the host computer is developed, or an external character font or logo is developed, thereby forming bit map information as output information and generating the same.
2. Related Background Art
Hitherto, such a kind of output apparatus, for instance, a printing apparatus such as a laser beam printer or the like comprises:
1. a controller section for receiving and processing print data from a host computer, for converting the print data into a video signal, and for transmitting the video signal to a printer mechanism section (printer engine); and PA1 2. a printer mechanism section (printer engine) for forming a visible image onto a paper (ordinary paper) by using an electrophotographic process on the basis of the video signal transmitted from the controller section.
In general, the controller section develops the print information of one page into an image memory as a bit map in accordance with the performance of the printer engine on the basis of the print data (character code, figure, image, print position, size designation, etc.) received from the host computer. The bit map image in the image memory is converted into the video signal and the video signal is transferred to the printer engine, thereby obtaining a print output.
Meanwhile, the printer engine makes a paper feed system in the printer engine operative on the basis of control information from the controller section and also forms an image onto a photo sensitive drum by a photo sensitive agent such as a toner or the like on the basis of the video signal transmitted from the controller section by using a light emitting device such as laser beam, LED array, liquid crystal shutter, or the like and transfers the formed image onto a paper (ordinary paper) fed by a paper feed. A stable print result is obtained from the visible image transferred onto the paper (ordinary paper) by using a fixing device of a high temperature and a high voltage.
In the printer as mentioned above, in the case where the controller section develops the print data transmitted from the host computer into a bit map, the print data is ordinarily developed in accordance with the performance (resolution, binary/multilevel value, monochrome/color, etc.) of the printer engine.
However, as the performance of the printer engine is improved, a memory capacity which is required for the controller to develop one page of bit map image increases.
It has been considered to avoid the needed increase in memory capacity by a method (band control) whereby the print data of one page is divided into a plurality of portions (segment units) and at least two memory areas into which the divided print data can be developed are prepared, the print data is sequentially developed on a segment unit basis synchronously with a paper feed speed of the printer engine, and the print data is transferred to the printer engine.
However, in general, after the paper feed has been started, the conveyance of the paper cannot be temporarily stopped during the conveyance of the paper.
Therefore, if the print data development time of a certain segment is longer than the paper feed time, there is a problem in that the correct print result is not obtained (overrun).